Free wheel clutch mechanism for bicycle drive train

ABSTRACT

An exercise bicycle including a frame having a seat and handlebars, a high-inertia flywheel having a hub at a center of rotation, the flywheel being rotatably supported on the frame at the hub, and a drive train including a drive sprocket, a crank arm attached to and extending from the drive sprocket, and a pedal attached to the crank arm, the drive train being rotatably supported by the frame. The drive train also includes a slave sprocket fixed to the flywheel at the hub, with the drive and slave sprockets connected in a direct-drive relationship, the drive train driveable in a forward and rearward directions to cause the flywheel to rotate. A clutch mechanism is positioned in engagement with the slave sprocket and the hub to create a frictional engagement between the sprocket and the hub, and to establish a break-free force threshold. When the drive train is actuated in the forward direction, the slave sprocket and the hub move together, and when the drive train is actuated in the rearward direction under the influence of a force greater than the break-free force threshold, the clutch mechanism slips between the slave sprocket and the hub, allowing the slave sprocket and the flywheel to move independently of one another. The clutch mechanism including a spring tensioner whereby the break-free force may be adjusted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.09/803,630 entitled “Free Wheel Clutch Mechanism for Bicycle DriveTrain,” filed Mar. 9, 2001; which is a continuation-in-part applicationof application Ser. No. 09/379,560, entitled “Free Wheel ClutchMechanism for Bicycle Drive Train,” filed Aug. 23, 1999, now U.S. Pat.No. 6,641,507; which is a continuation of application Ser. No.08/919,695, entitled “Free Wheel Clutch Mechanism for Bicycle DriveTrain,” filed Aug. 28, 1997, now U.S. Pat. No. 5,961,424; which is anon-provisional utility application claiming priority to provisionalApplication No. 60/038,726 entitled “Free Wheel Clutch Mechanism forBicycle Drive Train,” filed Feb. 18, 1997, which are hereby incorporatedby reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to free wheeling devices, and moreparticularly to a free wheel clutch mechanism useful with crank operatedexercise bicycles employing an inertia flywheel.

BACKGROUND

The benefit of exercising on a direct drive exercise bicycle is wellknown. Direct drive exercise bicycles typically utilize a high-inertiaflywheel driven by a fixed-gear drive train. The flywheel is driven bythe rider up to relatively high revolutions per minute (rpm). Because ofthe direct drive feature, the drive train must rotate at a fixed ratioof rpm as compared to the flywheel based on the gear ratio. One benefitof the direct drive exercise bicycle is that the direct drive gear trainprovides “pedal-through assistance” for the rider. The “pedal-through”feature assists the rider by pushing the pedal through the top andbottom dead center pedal positions to help make the transition smoothand efficient. Other benefits are derived from the direct driveinteraction between the inertia flywheel and the crank arms to which therider's feet are attached. The inertia flywheel provides a smooth,non-jerky pedaling rhythm which provides an efficient and rigorousexercise for the rider, especially at relatively high rpms, such as 60to 100 rpm.

In the application of this invention to an inertia flywheel exercisebicycle, positive drive is required to rotate the inertia wheel in orderto overcome regulated retardation torque applied by brake means used toprovide resistance against which the rider/operator works. The inertiawheel provides means for continued drive train (wheel to crank to leg)movements during those periods when the crank is in top dead center orbottom dead center positions, where the rider's legs are somewhat weakerin providing rotary motion to the activating crank arms. The flywheelaffords smooth and steady operation for the rider.

The direct drive relationship between the flywheel and the drive trainis also a drawback of exercising on this type of bicycle. The directdrive relationship is inconvenient when the rider wishes to quickly stopthe pedals, or loses the pedaling rhythm required to keep up with therotating flywheel. In the usual flywheel exerciser employing such adirect drive relationship, it is necessary for the rider/operator togradually decrease his cranking rate in order to slow down the inertiawheel. The rider cannot suddenly stop pedaling inasmuch as the inertiaflywheel continues to drive the crank arms.

Of similar importance is the desirability of providing pedal assist tothe rider/operator's legs when cranking at a speed slower than thatnecessary to positively drive the flywheel, and providing for a gradualreengagement and lockup between the pedal actuated drive shaft and thefree wheeling flywheel in order to avoid abrupt impact when reengagingthe moving flywheel.

It is with these issues in mind that the present invention wasdeveloped.

SUMMARY OF THE INVENTION

The present invention in general terms concerns a clutch mechanism foruse on an exercise bicycle, and consequently, the present inventionrecognizes that it is desirable to have a free wheeling mechanism for anexerciser of the inertia flywheel type which provides means forselectively disengaging the flywheel from the drive means. The clutchmechanism allows for the beneficial direct-drive connection between thedrive train and the flywheel, and also allows the drive train andflywheel to move independently from one another, or “break free”, when asufficient force is applied to the drive train or the flywheel.

In general, the invention is an exercise bicycle including a framehaving a seat and handlebars, a high-inertia flywheel having a hub at acenter of rotation, the flywheel being rotatably supported on the frameat the hub, and a drive train including a drive sprocket, a crank armattached to and extending from the drive sprocket, and a pedal attachedto the crank arm, the drive train being rotatably supported by theframe. The drive train also includes a slave sprocket fixed to theflywheel at the hub, with the drive and slave sprockets connected in adirect-drive relationship, the drive train driveable in a forward andrearward directions to cause the flywheel to rotate. A clutch mechanismis positioned in engagement with the slave sprocket and the hub tocreate a frictional engagement between the sprocket and the hub, and toestablish a break-free force. When the drive train is actuated in theforward direction, the slave sprocket and the hub move together under amechanical engagement, and when the drive train is actuated in therearward direction under the influence of a force greater than thebreak-free force, the clutch mechanism slips between the slave sprocketand the hub, allowing the slave sprocket and the flywheel to moveindependently of one another. There is no mechanical engagement betweenthe sprocket and the hub in the rearward direction as there is in theforward direction, established by the one-way bearing.

More specifically, the slave sprocket defines a sprocket collar mountedon the hub and also includes an engagement collar. A one-way bearing ismounted between the sprocket collar and the hub to allow the sprocketcollar to drive the hub when the sprocket collar is driven in a forwarddirection, and to allow the sprocket collar to spin independently of thehub when the sprocket collar is driven in the rearward direction. Anengagement flange fixedly mounted on the hub corresponds to theengagement collar, and compression means are mounted on the flywheel tobias the flange and the collar towards one another. A clutch materialmember is positioned between the engagement flange and the collar, andis clamped therebetween by the compression means to cause the engagementflange to move in conjunction with the sprocket collar. The engagementcreates a break-free force required to cause the sprocket collar to moveindependently of the engagement flange. When the drive train is actuatedin the forward direction, the sprocket collar and the engagement flangemove together, and when the drive train is actuated in the rearwarddirection and overcomes the break-free force, the engagement flangeslips with respect to the collar, allowing the sprocket collar and theflywheel to move independently of one another.

In another embodiment, the slave sprocket defines a sprocket collarmounted on the hub and defines an inner and outer engagement collars. Aone-way bearing is mounted between the sprocket collar and the hub toallow the sprocket collar to drive the hub when the sprocket collar isdriven in a forward direction, and to allow the sprocket collar to spinfreely on the hub when the sprocket collar is driven in the rearwarddirection. An inner engagement flange is fixedly mounted on the hubcorresponding to the inner engagement collar, and an outer engagementflange is fixedly mounted on the hub corresponding to the outerengagement collar. Compression means are mounted on the flywheel to biasthe inner flange and the inner collar towards one another, and to biasthe outer flange and the outer collar towards one another. A clutchmaterial member is positioned between the outer engagement flange andthe outer collar, and between the inner engagement flange and the innercollar, and clamped therebetween by the compression means to cause theinner and outer engagement flanges to move in conjunction with thesprocket collar. The engagement creates a break-free force required tocause the sprocket collar to move independently of inner and outerengagement flanges. When the drive train is actuated in the forwarddirection, the sprocket collar and the inner and outer flanges movetogether, and when the drive train is actuated in the rearward directionand overcomes the break-free force, the inner and outer engagementflanges slip with respect to the inner and outer collars, allowing thesprocket collar and the flywheel to move independently of one another.There are other embodiments of the invention disclosed which perform thesame function with very similar structure.

Another embodiment of the invention includes a frame with a high-inertiaflywheel having an axle and associated axle housing rotatably supportedon the frame. A sprocket is coupled to the flywheel. Typically, a chainor belt is connected between the sprocket and a second drive sprocketassociated with the pedals. A user pedaling the device thus drives theflywheel by pedaling. To provide a break free force between the flywheeland the sprocket, a clutch according to another aspect of the inventionis operably connected between the flywheel and the sprocket to engagethe sprocket with the flywheel with the break-free force. When the useris pedaling the device, the flywheel will oftentimes obtain a high levelof inertia. In addition, the user will oftentimes use some form of toeclip or clipless pedals to secure their shoes securely to the pedals.The clutch allows the user to disengage themselves from the high inertiarotation of the flywheel without disengaging their shoes from thepedals.

In one example, the clutch includes a one way bearing circumferentiallymounted on the axle housing. The sprocket is mounted on the axle housingand in engagement with the one way bearing. A clutch plate is operablyassociated with the sprocket, and a spring of some type is compressedbetween the clutch plate and the flywheel to engage the sprocket to theflywheel with the break-free force. One embodiment of the cutch plate,such as a clutch plate forming a ring shape, is circumferentiallydisposed about the hub. The spring, in one example, is a Belleville typewasher. In one particular embodiment, the Belleville washer iscompressed between the axle housing of the flywheel and the clutchplate. The clutch may also include a clutch plate collar operablyassociated with the sprocket, the clutch plate collar positioned betweenthe clutch plate and the spring.

Also, the invention includes an exercise bicycle frame for use with theclutch mechanism. The frame includes a front support, a rear support,and a brace member extending between the front and rear ground supports.In addition, front forks are included that have a top end and a bottomend, and are attached at the bottom end to the front ground support. Thefront forks rotatably support a high-inertia flywheel. A rear post isincluded that has a top member and a bottom member, the top memberattaching to the bottom member in a rear offset overlapping manner, therear post defining a top end and a bottom end. The rear post is attachedat the bottom end to the brace member. An articulated beam is attachedto and extends from the top end of the front forks downwardly andrearwardly to a midpoint between the front forks and the rear post, thenextends horizontally to the rear post at the intersection of the top andbottom members of the rear post. A rear truss extends from the topmember of the rear post to the rear support. A handlebar is attached atthe top end of the front forks, and a seat is attached at the top end ofthe rear post. A front area is defined by the front forks, articulatedbeam, rear post and brace member forming a five-sided polygon, and arear area is defined by the rear post, rear truss, and brace memberforming a five-sided polygon.

Accordingly, it is one object of the present invention to provide afree-wheeling clutch mechanism that allows an exercise bike to includethe direct-drive relationship between the drive train and the flywheel,and at the same time allow the drive train and the flywheel to turnindependently from one another under certain conditions.

Other aspects, features and details of the present invention can be morecompletely understood by reference to the following detailed descriptionin conjunction with the drawings, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exercise bicycle incorporating theclutch mechanism of the present invention.

FIG. 2 is a schematic representation of the drive train of the exercisebicycle shown in FIG. 1.

FIG. 3 is a schematic representation of the drive train of the exercisebicycle shown in FIG. 1.

FIG. 4 is a section taken along line 4—4 of FIG. 3.

FIG. 5A is a section taken along line 5A—5A of FIG. 2

FIG. 5B is a representative section similar to FIG. 5A showing theeffects of worn clutch material.

FIG. 5C is a representative section similar to FIG. 5A showing adifferent type of compression member.

FIG. 6 is a perspective view of a high-inertia flywheel incorporatingone embodiment of the clutch mechanism of the present invention.

FIG. 7 is an exploded view of the flywheel of FIG. 6.

FIGS. 8 and 9 are elevation and perspective views, respectively, of aportion of the clutch mechanism.

FIG. 10 is a side view of the sprocket collar member of the clutchmechanism of the present invention.

FIG. 11 is a top view of the sprocket collar shown in FIG. 10.

FIG. 12 is a section taken along line 12—12 of FIG. 10.

FIG. 13 is an enlarged front perspective view of the sprocket collar ofFIG. 10.

FIG. 14 is a side view of the clutch plate collar member of the clutchmechanism of the present invention.

FIG. 15 is a section taken along line 15—15 of FIG. 14.

FIG. 16 is a front perspective view of the clutch plate collar member ofthe clutch mechanism of the present invention.

FIG. 17 is a perspective view of a high-inertia flywheel incorporatingan alternative embodiment of the clutch mechanism of the presentinvention.

FIG. 18 is an enlarged perspective view of the embodiment of the presentinvention as shown in FIG. 17.

FIG. 19 is a section taken along line 19—19 of FIG. 18.

FIG. 20 is a representative section of the embodiment shown in FIG. 19,showing the effect of worn clutch material.

FIG. 21 is an enlarged perspective view of another embodiment of thepresent invention.

FIG. 22 is a section taken along line 22—22 of FIG. 21.

FIG. 23 is a section taken along line 23—23 of FIG. 22.

FIG. 24 is a representative section of an alternative embodiment similarto that shown in FIGS. 22, 23 and 24.

FIG. 25 is an elevation view of another embodiment of the presentinvention.

FIG. 26 is a section taken along line 26—26 of FIG. 25.

FIG. 27 is an elevation view of another embodiment of the presentinvention.

FIG. 28 is a section taken along line 28—28 of FIG. 27.

FIG. 29 is a section taken along line 29—29 of FIG. 28.

FIG. 30 is a representative section of another embodiment of the presentinvention.

FIG. 31 is a representative section of an alternative embodiment of thepresent invention.

FIG. 32 is a representative section of an additional alternativeembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In light of the above items, a free wheel clutch mechanism 40 has beendeveloped for use on direct-drive exercise bicycles 42 utilizing aninertia flywheel 44 (FIGS. 1–4). While the present invention isdescribed below associated with an exercise bicycle, it is contemplatedthat it could be used on normal bicycles or other exercise equipment,including magnetic resistive bicycles, air-resistance bicycles and othernon-bicycle exercisers (such as upper body exercisers), each havingrotary-driven mechanisms (wheels, etc.), in the proper circumstances.The free wheel clutch mechanism works in a direct-drive manner when therider pedals the bicycle in the forward direction (counter-clockwise inFIGS. 1 and 2, clockwise in FIG. 3), but has a release, or free wheel,characteristic when the rider applies a required force on the pedal (orto the drive train somewhere) opposite or against the forward pedalingdirection. Upon application of the appropriate opposite force (“breakfree force threshold”), the drive train free-wheels to allow the pedalsto turn in the opposite direction with respect to, or more slowly than,the rotation of the flywheel. The rider can then either simply drive thepedals at a relatively lower rpm than the normal gear ratio to theflywheel, stop the pedals, or can rotate the pedals backwards.

The opposite force required to be applied to the pedals to cause thefree wheeling action can be adjusted based on the design of the freewheel clutch mechanism, and is typically between 0.00 and 100 pounds,preferably 55 pounds at the pedals, depending on the application. Thebreak free force threshold is based on the static frictional engagementbetween the clutch material and the clutch plates which the clutchmaterial is clamped between, as well as the mechanical advantageprovided through the drive train. The clutch plates, as defined below,are on different members that in normal circumstances are to rotatetogether. The friction force between the clutch material and the clutchplates facilitates this relationship. At a certain point (the break freeforce threshold), the opposing clutch plates overcome the staticfrictional force and spin at different speeds (r.p.m.'s) in the samedirection, or in the opposite direction. The surface area of the clutchplates and the clutch plate material, the material property of theclutch plates and the clutch material, and the force at which the clutchplates clamp the clutch material are all factors that can bespecifically designed to affect the break free force threshold. Thebreak free force (as measured at the pedal) is affected also by the gearratio and the length of the crank arms.

The free wheel clutch mechanism 40 is integral to the drive train of theexercise bicycle. The drive or gear train includes the drive sprocket46, the crank arms 48 and associated pedals 50 attached to the drivesprocket, the drive axle assembly 52, the slave sprocket 54, and thechain or belt 56 that interconnects the drive and slave sprockets, asshown in FIG. 3. Typically, the drive sprocket is rigidly mounted to oneof the crank arms, and each crank arm is removably mounted to the driveaxle assembly. The drive axle assembly is positioned in the hub on theframe to allow rotating movement, in either direction of the crank arms.

As shown in FIG. 4, the free wheel clutch mechanism 40 includes asprocket collar 58 rotatably mounted on a slave axle assembly 60. Theslave sprocket 54 is attached to the flywheel 44 adjacent to the hub 62.The slave axle assembly is mounted in the hub, and attaches to the frameto allow the flywheel to rotate with respect to the frame, under theforce of the drive train through the movement of the slave axleassembly. The slave axle assembly is actually mounted in the hub, andincludes an axle housing. Typically, the slave sprocket is mounted onthe axle housing.

The free wheel clutch mechanism can be mounted in association with thedrive sprocket, cranks and drive axle assembly, or can be mounted inassociation with the slave sprocket, slave axle assembly and flywheel.The placement of the free wheel clutch mechanism is a matter of choicedependent on the particular implementation. The only difference betweenthe two positions of the free wheel clutch mechanism is that whenmounted in association with the slave sprocket, the actuation of thefree wheel clutch mechanism affects the movement of the chain and drivesprocket (slow down, stop or reverse). When the free wheel clutchmechanism is mounted in association with the drive sprocket, theactuation of the free wheel clutch mechanism allows the pedals andcranks to be slowed down, stopped, or reversed while the drive sprocket,chain and slave sprocket and flywheel continue to rotate. As describedherein, the free wheel clutch mechanism is mounted in association withthe slave sprocket.

More specifically as shown in FIGS. 4 and 5A, the free wheel clutchmechanism includes a sprocket collar 58 (in this case a “slave” sprocketcollar) that is mounted in a one-way drive relationship with the axlehousing 64 such that the rotation of the slave sprocket collar in onedirection directly drives the axle housing, and the rotation of theslave sprocket collar in the reverse direction does not drive the axlehousing (allows “free wheeling”). This free wheeling relationship isestablished by one-way bearings 66 or a ratchet and pawl structure usedbetween the slave sprocket collar and the axle housing.

The free wheeling motion of the slave sprocket collar 58 with respect tothe axle housing 64 (and hence hub 62 and flywheel 44) is tempered, orreduced, by clutch plates 68 and clutch or braking material 70 actingupon the slave sprocket collar. A clutch plate collar 69 is secured tothe axle housing 64 to fixedly position one end of the free wheel clutchmechanism 40. The clutch plates 68 are rigidly mounted to turn with theaxle housing (and hence the hub and flywheel), and are forced intocontact with the sprocket collar 58 by a biasing means, such as a springmember 72. The braking material 70 is positioned between the sprocketcollar and the clutch plates to provide a frictional interface betweenthe two. The braking material can be mounted to either the sprocketcollar, the clutch plates, or can be free-floating. The area of contactbetween the clutch plate and the sprocket collar (through the brakingmaterial) in combination with the compression force applied by thebiasing means 72, creates the “break free” force required to be appliedthrough the sprocket collar to allow the sprocket collar to “free wheel”on the axle housing. If the applied force is not sufficient to overcomethe “break free” force, then the sprocket collar is not able to freewheel on the axle housing.

The free wheeling clutch mechanism is self-adjusting under the biasforce to accommodate for the reduction in thickness of the brakingmaterial 70 wearing out through use. The clutch plates 68 “float” on theaxle housing to adjust and maintain contact with the sprocket collar asthe braking material becomes thinner.

Particular embodiments of the free wheeling clutch mechanism aredescribed in more detail below.

An exercise bicycle 42 incorporating the present invention is shown inFIG. 1. The bicycle includes a frame 80 supported on a support surfaceby ground engagement members 82, an adjustable seat 84, adjustablehandlebars 86, a flywheel 44 rotatably positioned between a pair offront forks 88 of the frame, and a gear train 54 attached to the frameadjacent to and below the seat.

The frame 80, as shown in FIG. 1, includes front and rear groundsupports 90 attached by a horizontal frame brace member 92 extendingthere between, front forks 88, and a rear post 94. The front forks andrear post are attached by an articulated beam 96 sloping from the top ofthe front forks down to approximately midway between the front forks andthe rear post, at which point the articulated beam extends horizontallyrearwardly to engage the rear post. The articulated beam thus includestwo members connected at an angle to one another, and extends betweenthe top of the forks to the approximate midpoint of the rear post.

An aperture is formed at the top of the forks to receive a handlebarpost 98, the handlebar post being vertically adjustable in the top ofthe forks by a pop-pin structure, as is known in the industry.Handlebars are attached to the top of the handlebar post in any knownmanner for use by the rider. An aperture is formed in the top of therear post for receiving a seat post 100. The seat post is verticallyadjustable in the rear post by a pop-pin structure, as is well known inthe art. The seat can be forwardly and rearwardly adjusted on the seatpost, such as by the mechanism disclosed in U.S. Pat. No. 4,772,069 toSzymski, incorporated herein by reference, in addition to beingvertically adjustable.

The rear post 94 includes a top member 102 and a bottom member 104. Thetop member 102 is attached to extend from the rear side of the bottommember 104, and extends beyond the top of the bottom member 104 in arear-offset overlapping manner. The articulated beam 96 is affixed tothe rear post 94 at the top of the bottom member 104 and the front sideof the top member 102. This attachment of the articulated beam to therear post forms a strong structural connection.

The crank arms 48 for each of the pedals 50 are attached to a hub 106which is supported by the rear post at a location along the height ofthe rear post where the bottom and top members of the rear postcoextend. The rear post 94 attaches to the horizontal frame member 92about midway between the front and rear ground support members 90. Arear truss 107 extends at an angle from the rear post 94 down to therear ground support member 90 for added strength. The frame isconstructed of rectangular or hollow cylindrical steel tubing, as isknown in the art. Rectangular tubing is preferred.

The front area defined by the forks 88, articulated beam 96, rear post94, and horizontal frame member 92 is a five-sided polygon. The reararea defined by the rear post 94, rear truss 107 and horizontal framemember 92 is also a five-sided polygon. A friction break 108 is mountedadjacent to the top of the front forks to selectively engage theopposing outer rims of the flywheel 44 to provide an additional frictionload against which the rider must work in exercising on the exercisebicycle. This frame design, to the geometry of the frame structure, isvery strong and durable, and is capable of withstanding the rigors offrequent use. The portion of the frame that supports the crank arms andchain ring is especially strong and durable in this design as a resultof the overlapped construction of the rear post 94.

As shown in FIGS. 1, 2 and 3, the drive or gear train (as describedabove) includes a drive sprocket 46 rotatably mounted on the frame,crank arms 48 and associated pedals 50 attached to the drive sprocketfor driving the drive sprocket, a free wheel clutch assembly 40, a slavesprocket 54 attached on the flywheel 44, and a chain 56 connecting thedrive sprocket to the slave sprocket, and to the free wheel clutchassembly. The chain could be replaced by a belt with accommodatingmodifications made to the drive and slave sprockets, with no adverseaffect on the operation of the free-wheeling clutch mechanism of thepresent invention.

As with a standard direct drive exercise bicycle, the rider pedals theexercise bicycle using the crank arms and pedals, to drive the drivesprocket 46. The chain 56, engaged between the drive sprocket and slavesprocket 54, causes the flywheel 44 to rotate at the given rpms based onthe gear ratio between the drive sprocket and the slave sprocket.

The free wheel clutch mechanism 40 engages the flywheel, as is describedbelow, to allow the transfer of rotational movement from the slavesprocket 54 to the flywheel 44 in a direct-drive relationship whendriven in the forward direction. Normal pedaling circumstances includethe use of the exercise bicycle during an organized exercise class orindividually, and include starting at 0.00 rpms and increasing anddecreasing the rpms as is required or desired for certain exerciseprograms, whether the rider is standing, sitting or alternating duringuse. The free wheel clutch mechanism 40 of the present inventionmaintains the “pedal-through” benefit of standard direct drive exercisebicycles. The pedal-through benefit helps the rider pedal continuouslyand smoothly through the top and bottom pedal positions where riderstypically are weakest.

The free wheel clutch mechanism 40 converts the direct driverelationship between the pedal revolutions and the flywheel revolutionsto a “free wheel” relationship to allow the pedals 50 to be stopped,reversed in direction, or rotated more slowly than the flywheel 44, whena sufficient force is applied in the reverse direction to either of thepedals or anywhere on the drive train (where the clutch mechanism ispositioned on the inertia wheel). Examples of the application of anopposite force include, but are not limited to, the intentionalapplication of the reverse force by the rider while pedaling, forinstance due to fatigue, or the contact of the pedal on the rider'slower leg when a foot is accidentally released from the pedal.

As shown in FIGS. 4, 5A, 5B, 6 and 7, the free wheel clutch mechanism 40mounts on the slave axle assembly 60 adjacent to the hub 62 of theflywheel 44. A cylindrical slave axle housing 64 is press-fit into acylindrical axial bore formed through the hub 62 of the flywheel. Theend of the axle housing extending from the hub is externally threaded toreceive the clutch plate collar 69.

In the description below, the terms “inside” and “inner” refer to theend closest to the flywheel 44, and the terms “outside” and “outer”refer to the end farthest from the flywheel. The clutch plate collar 69includes a hollow cylindrical main body 118 with internal threads at oneend for engagement with the external threads on the outer end of theaxle housing 64. The clutch plate collar 69 has an outer radiallyextending engagement flange 120 attached to the outside end of thecylindrical main body 118, and an inner radially extending engagementflange 122 moveably attached to the inside end of the cylindrical mainbody.

Referring to FIGS. 5A and 5B, the inner flange 122 is able to moveaxially (longitudinally) along the all or a portion of the length of thecylindrical main body 118 of the clutch plate collar 69. Referring toFIGS. 7, 8 and 9, the inner flange 122 has a central bore 124, defininga plurality of radially inwardly extending keys 126. Correspondinglongitudinally extending slots 128 are formed on the surface of thecylindrical main body of the clutch plate collar 69 at its inner end,and extend at least partially along the length of the main body, toreceive the keys 126 and allow the inner flange 122 to move (float)axially along the length of the cylindrical main body, to the extent ofthe length of the slots. The benefit of the axial movement of the innerflange of the clutch plate collar 69 is described in more detail below.When the cylindrical main body 118 is threadedly connected to the axlehousing 64, the inner flange is positioned so the keys are slidablyreceived in the slots, and the inner flange is retained on the end ofthe cylindrical main body by the hub 62 or the axle housing (by end ofaxle housing as shown in FIG. 5A). The intersection of the keys 126 inthe slots 128 make the inner flange turn with the cylindrical main body118.

A one-way bearing 66, such as an INA shell-type roller clutch as foundin the INA Bearing Company, Inc. of Fort Mill, S.C., catalog #305, 1988at page 164, is mounted on the cylindrical main body 118 of the clutchplate collar 69 between the end of the slots 128 and the outer flange120. The rollers of the bearing 66 engage the outer surface of thecylindrical main body member 118, and can slide (float) along the lengthof the main body, as described in more detail below. The one-way bearingpermits direct-drive in one direction, and free-wheeling in the otherrotational direction, also described in more detail below.

Referring to FIGS. 5A, 7, and 10–13, a sprocket collar 58 defines acentral bore and is positioned concentrically over the cylindrical mainbody member 118 of the clutch plate collar 69, and is attached to theouter race of the one-way bearing. The sprocket collar 58 defines anouter radially extending engagement collar 130 spaced away butsubstantially coextensive with the outer flange 120 of the clutch platecollar 69, an inner radially extending engagement collar 132 spaced awayfrom but substantially coextensive with the inner flange 122 of theclutch plate collar 69, and the slave sprocket 54 formed about the outersurface of the sprocket collar 58 and between the inner and outerextending collars 130 and 132. The chain 56 engages the slave sprocket54. The engagement collars 130 and 132 are extensions of the sidewallsof the sprocket collar, and provide more surface area if needed for theclutch-function they perform, as defined below.

The following explains the relative movement and drive characteristicsof the clutch plate collar 69, sprocket collar 58, and flywheel 44 withthe structure described at this point. When the slave sprocket 54 isdriven in the forward direction (clockwise with respect to FIG. 3,counter-clockwise with respect to FIGS. 1 and 2) by the chain 56, theone-way bearing 66 engages and causes the slave sprocket 54 to rotatethe sprocket collar 58, in turn rotating the clutch plate collar 69,which in turn rotates the axle housing 64, which causes the flywheel toturn. If the slave sprocket 54 is caused to move in the oppositedirection (counter-clockwise in FIG. 3, clockwise in FIGS. 1 and 2), theone-way bearing would allow the sprocket collar 58 to free-wheel on theclutch plate collar 69.

Ideally a friction clutch or braking material 70 in the form of a flatwasher (a disk with a central aperture formed therein) is positionedbetween the outer flange 120 of the clutch plate collar 69 and the outercollar 130 of the sprocket collar 58, and between the inner flange 122of the clutch plate collar 69 and the inner collar 132 of the sprocketcollar, as best shown in FIGS. 5A, 5B, and 7. The friction clutchmaterial 70 can be attached to either the outer flange 120 or the outercollar 130, and the friction clutch material 70 can be attached toeither the inner flange 122 or the inner collar 132, to anchor theclutch material. The clutch material 70 can be felt, cork, standardbrake material, or any material that provides a sufficient frictionalrelationship between the coextensive flanges and collars. Preferably,clutch facing, as shown in McMaster-Carr Company catalog number 101,1995, at page 2530, is used at a thickness of approximately 2.0 mm.Insert description for collar for inside diameter for free-floating andnot connected to either side. In some instances, such as when the clutchmaterial is not attached to either the clutch plate collar or thesprocket collar, but instead just floats between the two, a bearingwasher is attached to the perimeter of the central aperture to helpsupport the clutch material on the axle housing.

Compression means, such as a compression spring 72, is positioned aroundthe hub 62 of the flywheel 44 to engage the inner flange 122 of theclutch plate collar 69 to bias the inner flange toward the outer flange120 of the clutch plate collar. The spring 72, such as a jumbocompression spring in the McMaster-Carr catalog number 101, biases theinner flange 122 outwardly to clamp the clutch material 70 between itand the inner collar 132, and also clamps the clutch material 70 betweenthe outer collar 130 and the outer flange 120. The designed axialmovement of the inner race (such as by sliding) on the cylindrical mainbearing 66 (keys 126 sliding in the slots 128) allows the sprocketcollar 58 to float and transmit the force of the spring 72 to the outerflange 120. The combination of the bias force created by the spring 72,and the engagement of the clutch plate collar 69 and the sprocket collar58 with the clutch material 70 inbetween creates a friction force havingan upper limit (“break free”) force required to cause the sprocketcollar 58 to move independently of the clutch plate collar in thereverse direction.

For instance, where the spring force is approximately 225 pounds whenfully compressed, and the clutch material has an inner diameter of 1.65inches and an outer diameter of 2.52 inches, where two clutch materialdisks were used (FIG. 5B), the break free force has been tested to beapproximately 55 pounds at the pedal. It has been found that as thespring extends due to wear of the clutch material, the spring forcereduces to approximately 200 pounds, and the break free force actuallyincreases. This is believed to be due to the fact that the engagingsurfaces clamping the clutch material become polished and increase thesurface area, thus increasing the static friction force to be overcome.

The following explains the relative movement of the clutch plate collar69, sprocket collar 58 and flywheel 44 given the structure described tothis point. When the slave sprocket 54 is driven in the forwarddirection, as defined above, the one-way bearing creates thedirect-drive relationship with the flywheel 44 desired for this type ofexercise bicycle. When the slave sprocket 54 is driven in the backwarddirection, or there is a reverse force applied to the slave sprocket toattempt to rotate it in a direction opposite the direction of rotationof the flywheel, the one-way bearing does not drive the flywheel 44, butinstead allows the pedals to free wheel. However, the friction forcegenerated between the clutch plate collar 69 and the sprocket collar 58due to the engagement of the outer flange 120 and the outer collar 130with the inter-positioned clutch material 70, and the inner flange 122and inner collar 132 with the inter-positioned clutch material 70, actsto create a threshold friction force that must be overcome to allow therider to drive the sprocket collar 58 independent of the flywheel 44. Ifthe force applied by the rider to the pedals is large enough to overcomethe friction (“break free”) force, then the pedals cause the sprocketcollar 58 to turn independently of the clutch plate collar 69, with theclutch material 70 being rubbed and worn down in the process.

As the clutch material 70 wears down and becomes thinner, the spring 72extends to push the inner flange 122 (floating) along the slots tomaintain the appropriate force on the clutch material 70. The sprocketcollar 58 is also pushed outwardly to maintain the desired force, andresulting “break free” characteristics. The spring 72 thus allows forautomatic adjustment to compensate for the wear of the clutch material70. The spring 72 must be selected to have a relatively predictable andstable spring constant along its length of extension to insure thedevelopment of the proper friction forces. The spring can be replacedwith an elastomeric tube 73 having sufficient spring properties in theaxial direction, such as is shown in FIG. 5C. Some elastomeric materialshave very stable spring constants. One such suitable elastomericmaterial is a polyurethane made by Kryptonics Inc. of Louisville, Colo.Preferably, the tube 73 is approximately 1 inch long, 0.887 inches wheninitially compressed, and has a wall thickness of approximately 0.225inches. In addition, an adjustable compression spring could also be usedthat would allow the spring force to be adjusted to modify the breakfree force when desired.

The inner or outer clutch material 70 can be replaced by a bearing if itis desired to use only one clutch material 70. The break-free forcethreshold may be modified accordingly as a result.

Similar relative movement is found when the exercise bicycleincorporating the present invention is in use, and more clearly depictsthe advantages of the free wheel clutch mechanism of the presentinvention. When a rider is exercising on the exercise bicycle, theforward drive of the drive train causes the slave sprocket 54 to drivethe sprocket collar 58 in the direction of engagement of the one-waybearing, in the end to drive the flywheel 44 in a direct drive manner.If the rider desires, by applying a force of approximately 50 pounds inthe opposite direction, the threshold friction force between the clutchplate collar 69, the sprocket collar 58 and the clutch material 70 isovercome (the “break free” force), and the sprocket collar 58 can freewheel with respect to the clutch plate collar 69 and the flywheel 44.The sprocket collar 58 thus moves in the opposite direction with respectto the direction of rotation of the flywheel 44. The rider can thuspedal irrespective of the movement of the flywheel 44 until the frictionbetween the clutch plate collar and the sprocket collar (caused by theclutch material) reduces the rpms of the flywheel to a point where,based on the gear ratio, the rpms match to cause “lock-up”.

In a more extreme situation, if the foot of the rider slips off thepedal and the pedal strikes the rider's leg, a sufficient force isgenerated to overcome the “break free” force and the pedals can stop toreduce the chance of serious injury, letting the flywheel continue torotate until the friction force stops the rotation of the flywheel.

An axle 134 (FIGS. 5A and 5B) is positioned through the bore in the hub,with associated bearings to support the flywheel 44 and allow it torotate as driven by the gear train.

The one-way bearing is not necessary for the application to work on anexercise bicycle. However, without the one-way bearing the sprocketcollar would “free wheel” in the forward direction too when the driveforce was greater than the “break free” force, thus limiting the amountof force the rider could apply while pedaling the bicycle in the forwarddirection.

The one-way bearing 66 can be replaced by a spring-loaded ratchet andpawl drive mechanism found in normal bicycle applications, or other oneway drive mechanisms that can functionally replace the one-way bearingdescribed above. One such suitable commonly available ratchet and pawlmechanism is the LMA-8 from the LIDA Machinery Company, Ltd. of Taoyuan,Taiwan, as shown in the Taiwan Bicycle Source 1997–98 catalog at p. 370.

FIGS. 8 through 16 show details of some of the components describedabove.

An alternative embodiment of the free wheel clutch mechanism is shown inFIGS. 17–20. This alternative embodiment works on the same principle asthe first embodiment described above, except basically replaces thesingle large spring surrounding the hub 150 with the plurality ofsmaller springs 152 positioned between the flywheel 154 and the innerclutch plate 156. These plurality of springs 152 act to push the innerclutch plate 156 outwardly as the clutch material 158 wears down fromuse. As can best be seen in FIGS. 19 and 20, each of the plurality ofsprings surrounds a guide rod 160 mounted to the flywheel 154 which isreceived in a guide bore 162 mounted to and extending from the insideside of the inner clutch plate 156. The sliding interaction between theguide rod 160 and the guide bore 162 helps ensure that the inner clutchplate 156 is squarely moved outwardly under the bias of the springs asthe clutch material wears as a result of use. The interaction of theguide rod with the guide bore also causes the inner clutch plate 156 toturn with the flywheel 154 because the guide rods are laterally fixed inposition inside the guide bores, and as the guide rods turn with themovement of the flywheel, they cause the inner clutch plate to turnalso.

The axle housing 164 is press-fit into the hub 150 and extends from theflywheel 154, and has an outer end 166 with external threads. After theinner clutch plate 156 and associated compression springs 152 aremounted over the axle housing and positioned adjacent the hub, the slavegear collar 170 is positioned to engage the outer surface of the axlehousing 164 as in the previous embodiment, including having the samebearing structure 172. The slave gear collar has an inner surface 174adjacent the outer surface 176 of the inner clutch plate, between whichis positioned an inner clutch material washer 178. The inner clutchmaterial washer 178 is preferably fixed to either the outer surface ofthe inner clutch plate 156 or the inner surface of the slave gear collar170. A set of gear teeth 180 are formed about the outer circumference ofthe slave gear collar 170 for receiving the chain used to drive theflywheel.

The outer clutch plate 182 (or anchor plate) is then threaded on to theexternally threaded outer end 184 of the axle housing. An outer clutchmaterial washer 186 is positioned between the outer surface of the slavegear collar 170 and the inner surface of the outer clutch plate 182.Preferably, the outer clutch material washer 186 is fixed to either theouter surface of the slave gear collar 170 or the inner surface of theouter clutch plate 182. The outer clutch plate is fixed to the axlehousing by a lock-nut 188 to keep the outer clutch plate from turningloose under the force of the free wheel mechanism.

This alternative embodiment of the present invention operates infundamentally the same manner as the previously described embodiment.When a reverse force is applied to the drive train, normally through areverse force being applied to the pedals, and this reverse forceovercomes the “break free” force, the slave gear overcomes the frictionforce between the slave gear collar 170 and the outer clutch plate 182and inner clutch plate 156 which rotate with the flywheel 154. Thisallows the flywheel to continue spinning while the drive train is eitherstopped, pedaled backwards, or pedaled more slowly than the flywheel isspinning. The bearings 172 connecting the slave gear collar 170 to theaxle housing 164 are one-way bearings as described above, and when thedrive train is actuated in the normal or forward direction, the bearingslock and act as a direct drive connection between the drive train andthe flywheel.

When turned in the reverse direction, the bearings 172 allow the slavegear collar 170 to free-wheel, the free wheeling of which is restrictedby the frictional engagement of the slave gear collar 170 with thesurrounding clutch material 178, 186. The compression springs 152 applythe force to the inner clutch plate 156 which presses the inner clutchmaterial 178 against the slave gear collar. The slave gear collar 170can move longitudinally on the axle housing 164 (the bearing allowssmall amounts of movement in this direction) and thus transmits a forceto the outer clutch material 186, and finally to the outer clutch plate182. As the inner or outer clutch material wears down, the springs 152extend and push the inner clutch plate 156 outwardly and thus maintainthe contact necessary for the frictional engagement between the innerclutch plate 156, the inner clutch material 178, the slave gear collar170, the outer clutch material 186, and the outer clutch/anchor plate182.

FIG. 20 shows the adjusted relationship of the structure of thisalternative embodiment when the inner and outer clutch material washers178, 186 have worn down. Contrasting FIGS. 19 and 20, note the gapbetween the inner clutch plate 156 and the outer end of the hub 150. Thebearings 172 allow the slave gear collar 170 to move longitudinally onthe axle housing 164. Either one of the inner or outer clutch materials178, 186 can be replaced with a bearing if it is determined that theyare unnecessary.

Another alternative embodiment is shown in FIGS. 21–23. In thisalternative embodiment a Belleville washer 200 is mounted on the end ofthe axle housing 202 to bias the outer clutch plate 204 inwardly tocreate the desired friction force between the slave gear collar 206 andthe outer and inner clutch plates 204, 208 through the inner and outerclutch material washers 210, 212. In the second alternative embodiment aretainer 214 having an outwardly flanged inner end 215 is threaded on tothe end of the axle housing 202 extending from the hub 216, which hasexternal threads. The outwardly extending flange 215 of the retainerbutts up against the hub 216. The inner clutch plate 208 is thenpositioned next to the outwardly extending flange 215 and is retained inrotational position therewith by keys in slots or by any other suitableattachment method, such as welding (as shown in FIG. 22). Alternatively,the outwardly extending flange can act as the inner clutch plate.

An inner clutch material washer 210 is positioned adjacent to and incontact with the inner clutch plate 208, and the slave gear collar 206is mounted over the cylindrical body of the retainer 214. The slave gearcollar 206 is similar to the slave gear collars described in theprevious two embodiments and includes a bearing 218 positioned betweenthe slave gear collar 206 and the outer circumference of the retainer214, the bearing 218 being a one-way bearing allowing the slave gearcollar 206 to free-wheel when turned in a reverse direction, and lockingto provide a direct drive when turned in the forward direction. Gearteeth 220 are formed on the outer circumference of the slave gear collar206 for engagement with the chain of the drive train. An outer clutchplate 204 is positioned over the outer circumference of the retainer214. As shown in FIG. 23, the outer clutch plate 204 defines a centralbore 222 having at least one key 224 formed for mating insertion into acorresponding slot formed in the retainer 214. The mating key and slotrelationship between the outer clutch plate 204 and the retainer 214makes the outer clutch plate turn with the flywheel because the retainerturns with the flywheel 226 and the rotational interference between thekey and the slot causes the outer clutch plate 204 to turn also, inaddition to allowing the outer clutch plate to float or move inwardlyand outwardly with respect to the inner clutch plate 208 along the bodyof the retainer as the friction clutch material 210, 212 wears down.

The Belleville washer 200 is positioned about the end of the axlehousing to engage the outer clutch plate 204 with the bias force. Thebias force is created by an outer retainer 228 which defines acylindrical main body 230 having external threads and an outwardlyextending flange 232 at one end. The outer end of the axle housing 202defines internal threading 234 such that the cylindrical main body 230of the outer retainer 228 threads into the outer end of the axle housing202 to the point where the outwardly extending flange 232 abuts theouter end of the axle housing and also engages the inner rim of theBelleville washer 200 to compress the Belleville washer against theouter clutch plate 204. The compression of the Belleville washer 200against the outer clutch plate 204 causes the outer clutch plate to bebiased inwardly against the outer friction clutch material 212, which ispushed against the slave gear collar 206, which in turn is allowed torelatively float on the outer surface of the inner retainer 214 to pushagainst the inner clutch material 210 and in turn frictionally engagethe inner clutch plate 208.

As the slave gear collar 206 is driven in the forward direction by thedrive train, the one-way bearings 218 lock and create a direct driverelationship. When a sufficient reverse force is applied to the slavegear collar through the drive train, the one-way bearings release andallow the drive train collar to free-wheel under the influence of thefrictional relationship with the inner and outer clutch plates, similarto the interaction as described with respect to the embodiments above.

As the clutch material 210, 212 wears down and becomes thinner, theBelleville washer 200 extends to continue to create a friction force inthe clutch system by pushing the outer clutch plate 204 towards theinner clutch plate 208, thereby clamping the inner and outer clutchmaterial and the slave gear collar 206 therebetween.

Another alternative embodiment is disclosed in FIG. 24 which shows twoBelleville washers 240, 242 positioned back to back to allow for alonger adjustment stroke due to the wear of the inner and outer clutchmaterial washers 244, 246. In this third embodiment the outwardlyextending flange 248 of the second retainer 250 is enlarged to engagethe outer rim of the second Belleville washer 240. Belleville washersare very stiff and provide a great deal of force through the length oftheir extension.

Another alternative embodiment is disclosed in FIGS. 25–26. This fourthalternative embodiment utilizes a band-brake to create the frictionalbreak-free force. The band-brake 260 includes a retainer 262 fixed tothe flywheel 264 through which is positioned a spring loaded adjustmentscrew 266 which attaches to a housing 268. The housing includes twoguide slots 270 for slidably receiving tabs 272 formed on the flywheel.The housing is also fixed to the opposite ends of a belt 274. Theslidable engagement of the guide slots 270 on the tabs 272 help ensure aproperly oriented adjustment of the band-brake by the spring loadedscrew. The slots are formed in the housing of the band-brake, thehousing being attached to a belt, with the band-brake material 276attached to the inside surface a reinforcement sheathing 278 of the belt(as best seen in FIG. 26). The tabs, spring loaded threaded screw,housing and belt are all fixed to rotate with the flywheel. The springsurrounding screw 266 makes the system self-adjusting for wear of theband material by applying a preferably constant tension load on the beltthrough the housing. The selection of the spring constant properties ofthe spring determines the amount of tension on the belt, and the amountof adjustment (displacement) the band-brake can accommodate.

As best shown in FIG. 26, the slave gear collar 280 defines an annularaxial extension 282 which fits over a portion of the hub 284 withoutcontacting the hub. This annular extension 282 defines an inner rim 286and an outer rim 288, between which is an engagement surface 290. Theband contacts the engagement surface 290 between the inner rim and theouter rim. The slave gear collar 280 includes the same bearing system aspreviously described for one-way engagement with the outer surface ofthe axle housing 292. The proper positioning of the slave gear collar280 is maintained on the axle housing by a large washer 294 which istightly pressed against the outer surface of the slave gear collar by anut 296 to keep the slave gear collar from becoming imbalanced. A secondset of one-way bearings could be positioned between the annularextension 282 from the slave gear collar and the outer surface of thehub over which the slave gear collar annular extension is positioned.

As the drive train is actuated in the forward direction by the rider,the one-way bearing 298 between the slave gear collar 280 and the axlehousing 292 engages to cause a direct drive relationship between thedrive train and the flywheel, as in the previously describedembodiments. In the event a sufficient reverse force is applied to theslave gear collar through the drive train, the one-way bearing 298releases and allows the slave gear collar to free-wheel subject to thefrictional engagement of the slave gear collar and the belt 274. Theengagement surface 290 is in frictional engagement with the belt tocreate the “break free” force. The “break free” force is determined bythe tightness of the belt around the engagement surface on the annularextension 282 of the slave gear collar. This “break free” force resiststhe free wheeling of the slave gear collar on the axle housing 292 andprovides the beneficial pedal-through feature of traditional directdrive exercise bicycles. It also allows the drive train to free-wheelwhen a sufficient reverse force is applied to the drive train, likelythrough the pedals and cranks, to allow the drive train to be driven ata relatively lower RPM than the flywheel, depending on the gear ratio.

As the frictional brake material 276 wears down, the housing 268 isadjusted by tightening the screw 266 to move the housing, and thustighten the belt 274 around the annular extension 282 of the slave gearcollar 280 to maintain the desired frictional engagement, resulting inthe desired “break free” force.

Another alternative embodiment is shown in FIGS. 27–29. In thisembodiment, the slave gear collar 300 has the same structure as theprevious embodiment described, and is held in engagement with the axlehousing 302 in the same manner. A compression brake housing 304 ismounted in engagement with the flywheel 306 and includes means 308 forcausing engagement of arcuate compression members 310 with theengagement surface 312 on the slave gear (sprocket) collar annularextension 314, between the inner and outer rims 316, 318. The arcuatecompression members 310 have a hard backing 320 and a frictional clutchmaterial 32 (2 mated to their inner concave surface for engagement withthe slave gear collar annular extension 314. The brake housing 304includes means 308 for radially adjusting the compression of thecompression members against the annular extension 314, such as setscrews which are threadedly adjustable through the brake housing toengage the hard back surface 320 of the arcuate compression members 310to press the frictional material 322 of the compression members againstthe engagement surface 312 of the annular extension. These means can beself-adjusting to accommodate wear of the friction material, such as bybeing spring-loaded set-screws. As the frictional clutch material wearsdown, the set screws 324 can be used to maintain the proper compressionof the compression members 310 against the engagement surface 312, whichcreates the desired “break free” force.

This embodiment operates in the same manner to allow a break free clutchmechanism on the flywheel as the previously described embodiments. Thebrake housing 304 is held in rotational fixed orientation with theflywheel by a pin 326 positioned through a slot 328 in the brakehousing. The movement of the pin in the slot allows for uneven wear ofthe compression members 310.

Another alternative embodiment is shown in FIG. 30. Only one side, theinner side 329 as shown, of the sprocket collar 330 is used to create africtional engagement with an engagement flange 332 attached to the axlehousing 334 at the hub 336 of the flywheel 338. The sprocket collar ispositioned on a sheath 333 threadably engaging the axle housing 334 atthe hub 336, with a one-way bearing 337 (or ratchet and pawl mechanism)positioned between the sprocket collar and the sheath 333 for the samepurpose as disclosed above with many of the other embodiments. Clutchmaterial 340 is positioned between the side 329 of the sprocket collar330 and the engagement flange 332, and can be attached to either one, tocreate the frictional engagement therebetween. The engagement flange ismoveable along the axle housing of the hub to allow the friction forceto be kept at a relatively constant level as the clutch material wearsout. This self-adjustment, as described above, occurs when the spring342, or other means, presses the engagement flange outwardly from thehub to clamp the clutch material against the inner side 329 of thesprocket collar 330. The sprocket collar 330 is supported on the innerand outer sides by an inner 344 and outer 346 bearing, respectively. Theinside edge 335 of the sheath forms the outer race for the inner bearing344, while the sprocket collar forms the inner race for both the inner344 and outer 346 bearings. The outer race 348, or cone, threadedlyengages the outer end of the sheath 333 to hold the sprocket collar 330in place and provide a thrust bearing against which the spring 342pushes.

FIG. 31 illustrates an additional alternative embodiment of a free wheelclutch mechanism 360. This embodiment operates in fundamentally the sameway as previously described embodiments. When a reverse force is appliedto the drive train, normally through a reverse force being applied tothe pedals, and this reverse force overcomes the break-free force, theslave gear overcomes the friction force between the slave gear collarand the inner and outer clutch plates which rotate with the flywheel.

In this alternative embodiment, preferably a Belleville washer 362 iscircumferentially mounted on an axle housing 364 between an inner clutchplate collar 366 and a spring tensioner 368 to bias the inner clutchplate 366 outwardly to create the desired friction force between theslave gear collar 370 and the inner and outer clutch plates (366, 372)through the inner and outer clutch plate material washers (374, 376).Alternatively, a biasing member such as a coil spring may be used inplace of the Belleville washer 362.

The spring tensioner 368 is coupled to the axle housing 364, andpositioned between the flywheel 378 and the inner clutch plate collar366. In this embodiment, the outside circumference 379 of the axlehousing 364 extending between the outside edge 380 of the flywheel 378and the inner clutch plate 366 is threaded. The spring tensioner 368defines an internally threaded cylinder that threadedly engages theoutside circumference 379 of the axle housing 364. Preferably, thespring tensioner 368 defines an outwardly extending flange 381circumferential to the axle housing 364 that is adapted to center theBelleville washer 362 about the axle housing 364.

To provide space for the spring tensioner 368, a portion of the flywheelhub 364 adjacent the free wheel clutch mechanism 360 is preferablyremoved. As shown in FIG. 22, preferably the portion of the hub 216 thatextends outwardly from the main body of the flywheel 226 along the axlehousing 202 to the inner retainer 214 (366) is removed. Alternatively, alonger axle housing than illustrated in FIG. 22 may be used.Alternatively, the portion of the flywheel hub is not removed, and theBelleview washer 362 is positioned between the outside edge 215 of theflywheel hub 216 and the inner clutch plate collar 366, and a springtensioner is not included.

In the preferred configuration, the Belleville spring 362 is positionedbetween the inner clutch plate collar 366 and the spring tensioner 368to create the bias force. The bias force is created by compression ofthe Belleville spring 362 between the spring tensioner 368 and the innerclutch plate collar 366. One advantage of this embodiment is that thespring tensioner 368 may be rotated about the threaded outsidecircumference 379 of the axle housing 364 to move the spring tensioner368 outwardly or inwardly, and accordingly easily adjust the break-freeforce of the flywheel. Rotating the spring tensioner about the threadedaxle housing 379 so as to move the spring tensioner 368 outwardly willincrease the compression of the Belleville washer, and hence increasethe break-free force. Rotating the spring tensioner 368 about thethreaded axle housing 379 so as to move the spring tensioner inwardlywill decrease the compression of the Belleville washer 362, and hencedecrease the break-free force. The compression of the Belleville washer362 against the inner clutch plate collar 366 causes the inner clutchplate to be biased inwardly against the inner friction material 376,which is pushed against the slave gear collar 370, which in turn ispushed against the outer clutch plate material 374 and in turnfrictionally engages the outer clutch plate collar 372.

An additional advantage of this embodiment is that frictional engagementof the free wheel clutch mechanism 360 may be applied with preferablyabout 1.5 turns of the spring tensioner 368 about the axle housing. Thisprovides for simple removal and unloading of the device. Additionally,as the clutch material (374, 376) wears down and becomes thinner, thecompression of the Belleville washer 362 may be readily adjusted by wayof rotation of the spring tensioner 368. As with other embodimentsdescribed herein, as the clutch plate material (374, 376) wears down,the Belleville washer 362 will extend and maintain the friction force onthe clutch system 360. The break-free force, however, will decreaseunless appropriate adjustments are made with the spring tensioner 368.

The inner clutch plate washer 376 is positioned adjacent to and incontact with the inner clutch plate 366, and the slave gear collar 370is similar to the slave gear collars described in previous embodimentsand includes a bearing 382 positioned between the slave gear collar 370and the outer circumference of the outer clutch plate body 372, thebearing 382 being a two-way bearing allowing the slave gear collar 370to free-wheel when turned in a reverse direction, and locking to providea direct drive when turned in the forward direction. Preferably, an INABearing Company shell-type roller clutch bearing as described previouslyherein is used. Gear teeth are formed on the outer circumference of theslave gear collar 370 (or sprocket) for engagement with the chain of thedrive train. As the slave gear collar 370 is driven in the forwarddirection by the drive train, the one-way bearings lock and create adirect drive relationship. When sufficient reverse drive force isapplied to the slave gear collar 370 through the drive train and thebreak-free force is exceeded, the one-way bearings release and allow thedrive train collar to free-wheel under the influence of the frictionalrelationship with the inner and outer clutch plates, similar to theinteraction described with respect to the other embodiments herein.

In this embodiment, the clutch plate material (374, 376) is preferably ahard plastic such as Polyethylene, which has advantageous wearcharacteristics. Using the hard plastic as the clutch plate material,preferably 900 lb. of friction force is applied to the freewheel clutch360 through the Belleville washer 362 using the spring tensioner 368. Toadjust the friction, or break free force, the spring tensionerpreferably includes a radial hole in its outside circumference in whicha dowel may be inserted to rotate the spring tensioner. The frictionforce on the Belleville washer may range from between 0 lb. to about1200 lb. depending on how the spring tensioner is adjusted. At thepedals, the break-free torque is preferably about 344 in.-lb. to about444 in.-lb. The preferred specifications of the Belleville washer are:OD=55.8 mm; ID=28.6 mm; Thickness (uncompressed)=2 mm; 830 (+/−20) lb.at 75% compression; 1110 (+/−30) lb. at 100% compression; Material=SAE1075.

Similar to the embodiment illustrated in FIG. 5 a, the outer clutchplate collar 372 includes a hollow cylindrical main body 384 withinternal threads at one end for engagement with the external threads onthe outer end 386 of the axle housing 364. The clutch plate collar 372defines an outer radially extending engagement flange 388 attached tothe outside end of the main body, and an inner radially extendingflange, which is the inner clutch plate 366, moveably attached to theinside end of the cylindrical main body 384. The inner clutch plate 366is able to move axially (longitudinally) along all or a portion of thelength of the cylinder main body 384 of the outer clutch plate collar372. As shown with reference to the embodiments illustrated in FIGS. 7,8, and 9, the inner flange 366 has a central bore 124 defining aplurality of radially inwardly extending keys 126. Correspondinglongitudinally extending slots 128 are formed on the surface of thecylindrical main body of the outer clutch plate collar 372 at its innerend, and extend at least partially along the length of the main body, toreceive keys 126 and allow the inner flange to move (float) axiallyalong the length of the cylindrical main body 384, to the extent of thelength of the slots. When the cylindrical main body 384 is threadedlyconnected to the axle housing 364, the inner flange 366 is positioned sothe keys 126 are slidably received in the slots, and the inner flange366 is retained on the end of the cylindrical main body 384 by the axlehousing 364. The intersection of the keys in the slots make the innerflange turn with the cylindrical main body.

FIG. 32 illustrates an additional alternative embodiment of a free wheelclutch mechanism 390. This embodiment operates in fundamentally the sameway as previously described embodiments. When a reverse force is appliedto the drive train, normally through a reverse force being applied tothe pedals, and this reverse force overcomes the break-free force, theslave gear overcomes the friction force between the slave gear collarand the inner and outer clutch plates which rotate with a flywheel 391.

In this alternative embodiment, a Belleville washer 392 iscircumferentially mounted on an axle housing 394 between an inner clutchplate collar 396 and a circumferential wall 398 of the axle housing tobias the inner clutch plate 396 outwardly to create the desired frictionforce between a slave gear collar 400 and the inner and an outer clutchplate (396, 402) through an inner and an outer clutch plate materialwasher (404, 406). Alternatively, a biasing member such as a coil springmay be used in place of the Belleville washer 392.

The inner clutch plate washer 404 is positioned adjacent to and incontact with the inner clutch plate 396. The slave gear collar 400 issimilar to the slave gear collars described in previous embodiments andincludes a bearing 408 positioned between the slave gear collar 400 andthe outer circumference of the outer clutch plate body 402. The bearing408 is a two-way bearing allowing the slave gear collar 400 tofree-wheel when turned in a reverse direction, and locking to provide adirect drive when turned in the forward direction. In one example, anINA Bearing Company shell-type roller clutch bearing issued as describedpreviously herein. Gear teeth are formed on the outer circumference ofthe slave gear collar 400 (or sprocket) for engagement with the chain ofthe drive train. As the slave gear collar 400 is driven in the forwarddirection by the drive train, the one-way bearings lock and create adirect drive relationship. When sufficient reverse drive force isapplied to the slave gear collar 400 through the drive train and thebreak-free force is exceeded, the one-way bearings release and allow thedrive train collar to free-wheel under the influence of the frictionalrelationship with the inner and outer clutch plates, similar to theinteraction described with respect to the other embodiments herein.

In one example, the clutch plate material (404, 406) is a hard plasticsuch as Polyethylene, which has advantageous wear characteristics. Thefriction force on the Belleville washer may range from between 0 lb. toabout 1200 lb. depending in part on the distance between the wall 398and the outer clutch plate 396, which determines the amount by which theBelleville washer is compressed. At the pedals, the break-free torquecan range from about 344 in.-lb. to about 444 in.-lb., in one example.The specifications of one embodiment of the Belleville washer that workswith embodiments of the invention are: OD=55.8 mm; ID=28.6 mm; Thickness(uncompressed)=2 mm; 830 (+/−20) lb. at 75% compression; 1110 (+/−30)lb. at 100% compression; Material=SAE 1075.

Similar to the embodiment illustrated in FIG. 5 a, the outer clutchplate collar 392 includes a hollow cylindrical main body 410 withinternal threads at one end for engagement with the external threads onthe outer end 412 of the axle housing 394. The clutch plate collar 402defines an outer radially extending engagement flange 414 attached tothe outside end of the main body, and an inner radially extendingflange, which is the inner clutch plate 396, moveably attached to theinside end of the cylindrical main body 410. The inner clutch plate 396is able to move axially (longitudinally) along all or a portion of thelength of the cylinder main body 410 of the outer clutch plate collar392.

As shown with reference to the embodiments of the invention illustratedin FIGS. 7, 8, and 9, the inner flange 396 has a central bore 124defining a plurality of radially inwardly extending keys 126.Corresponding longitudinally extending slots 128 are formed on thesurface of the cylindrical main body of the outer clutch plate collar392 at its inner end, and extend at least partially along the length ofthe main body, to receive keys 126 and allow the inner flange to move(float) axially along the length of the cylindrical main body 410, tothe extent of the length of the slots. When the cylindrical main body410 is threadedly connected to the axle housing 394, the inner flange396 is positioned so the keys 126 are sidably received in the slots, andthe inner flange 366 is retained on the end of the cylindrical main body410 by the axle housing 394. The intersection of the keys in the slotsmake the inner flange turn with the cylindrical main body.

It is contemplated that these free wheel clutch mechanism structuresdescribed herein could be mounted on the drive sprocket of the drivetrain, in addition to the slave sprocket of the drive train. It is alsocontemplated that a one-way bearing need not be used in allcircumstances, in which case the clutch mechanism would be caused toslip if the break-free force threshold was reached in either the forwardor rearward drive-train direction.

Embodiments of the present invention and many of its improvements havebeen described with a degree of particularity. The previous descriptionis of examples for implementing the invention, and the scope of theinvention should not necessarily be limited by this description. Thescope of the present invention is defined by the scope of the followingclaims.

It is contemplated that these free wheel clutch mechanism structuresdescribed herein could be mounted on the drive sprocket of the drivetrain, in addition to the slave sprocket of the drive train. It is alsocontemplated that a one-way bearing need not be used in allcircumstances, in which case the clutch mechanism would be caused toslip if the break-free force threshold was reached in either the forwardor rearward drive-train direction.

Various embodiments of the present invention and many of itsimprovements have been described with a degree of particularity. Theprevious description is of examples for implementing the invention, andthe scope of the invention should not necessarily be limited by thisdescription. The scope of the present invention is defined by the scopeof the following claims.

1. An exercise bicycle comprising: a frame; a high-inertia flywheelhaving an axle housing defining a wall, the axle housing rotatablysupported on the frame; a sprocket coupled with the flywheel; a clutchoperably connected between the flywheel and the sprocket to engage thesprocket with the flywheel with a break-free force, the clutchincluding: a one way bearing circumferentially mounted on the axlehousing; the sprocket circumferentially mounted in engagement with theone way bearing; a clutch plate circumferentially disposed about theaxle housing and operably connected with the sprocket; a clutch platecollar circumferentially disposed about the axle housing adjacent theclutch plate; and a Belleville washer compressed between the wall of theaxle housing and the clutch plate collar to compress the clutch platebetween the clutch plate collar and the sprocket, and to engage thesprocket to the flywheel with the break-free force.
 2. A clutchmechanism for an exercise bicycle, the exercise bicycle having a frameand a high-inertia flywheel having an axle housing, the flywheel beingrotatably supported on the frame at the hub, the exercise bicyclefurther having a drive train supported on the frame and engaged with theflywheel and driveable in a forward direction and a rearward directionto cause the flywheel to rotate, the clutch mechanism comprising: asprocket operably connected with the flywheel; a clutch operablyconnected between the sprocket and the flywheel to engage the sprocketto the flywheel with a break-free force, the clutch further comprising:a one way bearing circumferentially mounted on the axle housing; thesprocket circumferentially mounted in engagement with the one waybearing; a clutch plate circumferentially disposed about the axlehousing and operably associated with the sprocket; a clutch plate collarcircumferentially disposed about the axle housing adjacent the clutchplate; and a Belleville washer compressed between the axle housing andthe clutch plate collar to compress the clutch plate between the clutchplate collar and the sprocket, and to engage the sprocket to theflywheel with a break-free force.
 3. The clutch mechanism of claim 2,the clutch plate comprising an inner clutch plate adjacent an insideedge of the slave sprocket, and an outer clutch plate adjacent an outeredge of the slave sprocket.
 4. The clutch mechanism of claim 3, theclutch including an inner clutch washer positioned between the outerclutch plate and the slave sprocket, and an outer clutch washerpositioned between the outer clutch plate and the slave sprocket.
 5. Theclutch mechanism of claim 4, wherein the inner clutch washer and theouter clutch washer are polyethylene.
 6. The exercise bicycle of claim1, the clutch plate comprising an inner clutch plate adjacent an insideedge of the slave sprocket, and an outer clutch plate adjacent an outeredge of the slave sprocket.
 7. The exercise bicycle of claim 6, theclutch including an inner clutch washer positioned between the outerclutch plate and the slave sprocket, and an outer clutch washerpositioned between the outer clutch plate and the slave sprocket.
 8. Theclutch mechanism of claim 7, wherein the inner clutch washer and theouter clutch washer are polyethylene.